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Re: Primary magnetic field plots

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Terry,

Very cool pictures.

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Here are the flux lines of the coil set up with the MOT under the coil and a fan to the right side:


Very few flux lines make it up to the top terminal and the aluminum fan seems to be transparent to magnetic flux. The big iron transformer bends the lines around.

At 60Hz, I would think the Aluminum is fairly transparent to H field (skin depth maybe greater than AL thickness, but haven't calculated it). What frequency did you use for the simulation??? and does the program handle eddy currents effects??? If the program uses only the primary current as a H field generator, its results may not be accurate. If it also calculates eddy currents and add the resulting H fields to the total, you should see a different pattern with increased frequency. If the frequency is high enough, I would think the AL should affect the flux lines to a higher degree and act as a shield.

We then can look at the B field (in Teslas ;-))


The transformer attracts some of this field and is energized by it slightly.

B=uH permeability is high and shortens the magnetic path, so reluctance is lower thru the transformer core than thru the air.

The plot of field energy is where the "power" is at:


The power stays "very close" to the primary coil turns. That is why those big metal things in the area of the primary do not affect things much. If we increase the sensitivity, we can see more detail:


The energy still clings very close to the primary but you can see it touching the secondary now. If we really turn up the magnification, you can see the transformer having a tiny effect:


Sort of cool!!